.TH MS_READLEAPSECONDS 3 2016/10/01 "Libmseed API"
.SH NAME
ms_readleapseconds - Read a leap second file into a global buffer

.SH SYNOPSIS
.nf
.B #include <libmseed.h>

.BI "int  \fBms_readleapseconds\fP ( char *" envvarname " );"

.BI "int  \fBms_readleapsecondfile\fP ( char *" filename " );"
.fi

.SH DESCRIPTION
These functions read a leap seconds file and store a list of leap
seconds in an internal, global list.  The leap seconds are used to
determine the proper end time of a record (and consquently a trace).
The use of this facility causes the leap second indication in the
fixed section data header to be ignored.

The \fBms_readleapseconds\fP function takes and environment variable
name that is expected to contain the name of a leap seconds file.  The
\fBms_readleapsecondfile\fP function takes the name of a leap second
file.

.SH LEAP SECOND LIST FILE
The leap second list file is expected to contain a list of leap second
times and TAI-UTC difference values.  The first column should be time
stamps as seconds since the NTP epoch (Jan. 1 1900).  The second
column should be an integer number of seconds that specify the
difference between TAI and UTC.

Usually the most recent version of this file is available here:
https://www.ietf.org/timezones/data/leap-seconds.list

.SH RETURN VALUES
\fBms_readleapseconds\fP returns the number of leap seconds read on
success, -1 on file read errors and -2 when the environment variable
is not set.

\fBms_readleapsecondfile\fP returns the number leap seconds read on
success and -1 on errors.

.SH AUTHOR
.nf
Chad Trabant
IRIS Data Management Center
.fi